Question

(FMP-RS) As raízes da equação x² + x - 2 = 0 são: A 1, -2 B 1, 2 C -1, 2 D -1, -2 E 1, 1​

Answer 1

$\Large\boxed{\begin{array}{l}\sf x^2+x-2=0\\\sf\Delta=b^2-4ac\\\sf\Delta=1^2-4\cdot1\cdot(-2)\\\sf\Delta=1+8\\\sf\Delta=9\\\sf x=\dfrac{-b\pm\sqrt{\Delta}}{2a}\\\\\sf x=\dfrac{-1\pm\sqrt{9}}{2\cdot1}\\\\\sf x=\dfrac{-1\pm3}{2}\begin{cases}\sf x_1=\dfrac{-1+3}{2}=\dfrac{2}{2}=1\\\\\sf x_2=\dfrac{-1-3}{2}=-\dfrac{4}{2}=-2\end{cases}\\\\\sf S=\{1,-2\}\\\huge\boxed{\boxed{\boxed{\boxed{\sf\maltese~alternativa~A}}}}\end{array}}$

Answer 2

Resposta:

$\textsf{Leia abaixo}$

Explicação passo a passo:

$\mathsf{x^2 + x - 2 = 0}$

$\mathsf{x^2 + x - 2x + 2x- 2 = 0}$

$\mathsf{x^2 - x + 2x- 2 = 0}$

$\mathsf{x(x - 1) + 2(x- 1) = 0}$

$\mathsf{(x + 2).(x - 1) = 0}$

$\boxed{\boxed{\mathsf{S = \{-2;1\}}}}\leftarrow\textsf{letra A}$